Back brace



FIG. 1 is a perspective view showing a new design for a back brace;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a bottom view thereof;

FIG. 5 is a top view thereof;

FIG. 6 is a left side view thereof; and,

FIG. 7 is a right side view thereof.

The broken lines in the figures are for the purpose of illustrating portions of the back brace and form no part of the claim. 

CLAIM The ornamental design for a back brace, as shown and described. 